The iPhone 8 Plus even lost to iPhone 7 Plus' front camera. Worse dynamic range and in low light. If you saw comparisons of the Note8 or Pixel 2 XL vs 8 Plus, then you pretty much had a good idea how the X would fare.
I don't think the X is that far behind especially during the daytime shots outside. But low light, dynamic range, front cam, audio recording for video, the other two beat it.
Wait for Gen 2. Apple should have released the 8 back in March with A10X chip and call it 7s. Give it time to sell although it would tick off 7 owners. Then give X the A11, 4 GB RAM, and slightly updated cameras.
By releasing both six weeks apart and announcing them on the same day, there wasn't much differentiation except in design, OLED, Face ID, and Animoji. 8 Plus never got a chance to shine and X never had time to differentiate itself.
8 is a lazy product. X is a rushed one. X just cannibalized the 8's chances. Wait for the 2018 iPhones. We know Apple's routine of milking the same design for a minimum of four years.